Heatstroke symptoms include:

- High body temperature. A body temperature of 104 F (40 C) or higher is the main sign of heatstroke.

- Altered mental state or behavior. Confusion, agitation, slurred speech, irritability, delirium, seizures and coma can all result from heatstroke.

- Alteration in sweating. In heatstroke brought on by hot weather, your skin will feel hot and dry to the touch. However, in heatstroke brought on by strenuous exercise, your skin may feel moist.

- Nausea and vomiting. You may feel sick to your stomach or vomit.

- Flushed skin. Your skin may turn red as your body temperature increases.

- Rapid breathing. Your breathing may become rapid and shallow.

- Racing heart rate. Your pulse may significantly increase because heat stress places a tremendous burden on your heart to help cool your body.

- Headache. Your head may throb.

First Aid for Heat Stroke

If you suspect that someone has a heat stroke, immediately call 911 or transport the person to a hospital. Any delay seeking medical help can be fatal.

While waiting for the paramedics to arrive, initiate first aid. Move the person to an air-conditioned environment -- or at least a cool, shady area -- and remove any unnecessary clothing.

If possible, take the person's core body temperature and initiate first aid to cool it to 101 to 102 degrees Fahrenheit. (If no thermometers are available, don't hesitate to initiate first aid.)

Try these cooling strategies:

- Fan air over the patient while wetting his or her skin with water from a sponge or garden hose.
- Apply ice packs to the patient's armpits, groin, neck, and back. Because these areas are rich with blood vessels close to the skin, cooling them may reduce body temperature.
- Immerse the patient in a shower or tub of cool water, or an ice bath.

If emergency response is delayed, call the hospital emergency room for additional instructions.